The purpose of this proposal is to study the effect of hypercalcemia on AQP2 expression in vitamin D induced hypercalcemia and NDI in rats. We aim to identify proteins and phosphoproteins with altered abundances in the IMCD of vitamin D induced hypercalcemia and NDI in rats and their possible cellular functions. To achieve these general purposes, we have developed four study goals as following.
1. To determine the time course of AQP2 expression and time course of countercurrent multiplication defect (NKCC2, pNKCC2) in vitamin D induced hypercalcemia in rats.
2. To determine whether activation of the PKB/Akt-kinase pathway or phosphorylation of glycogen synthase kinase type 3? (GSK3?) or the mitogen-activated protein kinases (MAPK) or calcium sensing receptor (CaR) occur in IMCD of hypercalcemia induced NDI rats.
3. To identify proteins and phosphoproteins which are involved in regulation of AQP2 expression in renal collecting duct cells of these rats by LC-MS/MS coupled with pathway analysis.
4. To validate newly finding proteins and phosphoproteins which may involve in alteration of AQP2 expression in renal collecting duct cells of these rats by immunoblots.
